import copy
import json
import os
import subprocess
import sys
from datetime import datetime

import gradio as gr
import torch
from huggingface_hub import hf_hub_download, list_repo_files
from gradio.blocks import Blocks as _GradioBlocks

from config import CONFIG
from inference import _build_tokenizers, _resolve_device, load_model, run_inference


RESULTS_DIR = "generated_results"
DEFAULT_ANALYSIS_OUT = "analysis/outputs"
os.makedirs(RESULTS_DIR, exist_ok=True)
MODEL_CACHE = {}


# HF Spaces currently installs gradio[oauth]==5.0.0. In that stack, API schema
# generation can crash with:
# TypeError: argument of type 'bool' is not iterable
# Guard it so UI still serves even if API metadata generation fails.
_ORIG_GET_API_INFO = _GradioBlocks.get_api_info


def _safe_get_api_info(self):
    try:
        return _ORIG_GET_API_INFO(self)
    except TypeError as e:
        if "bool' is not iterable" in str(e):
            return {"named_endpoints": {}, "unnamed_endpoints": {}}
        raise


_GradioBlocks.get_api_info = _safe_get_api_info


def discover_checkpoints():
    found = []
    for root in ("ablation_results", "results7", "results"):
        if not os.path.isdir(root):
            continue
        for entry in sorted(os.listdir(root)):
            ckpt = os.path.join(root, entry, "best_model.pt")
            if not os.path.exists(ckpt):
                continue
            found.append(
                {
                    "label": f"{entry}  [{root}]",
                    "path": ckpt,
                    "experiment": entry,
                    "root": root,
                }
            )
    repo = os.getenv("HF_CHECKPOINT_REPO", "").strip()
    if repo:
        branch = os.getenv("HF_CHECKPOINT_REVISION", "main").strip() or "main"
        try:
            for fname in list_repo_files(repo_id=repo, repo_type="model", revision=branch):
                if not fname.endswith("/best_model.pt") and fname != "best_model.pt":
                    continue
                local_path = hf_hub_download(repo_id=repo, filename=fname, revision=branch, repo_type="model")
                parent = os.path.basename(os.path.dirname(fname)) if "/" in fname else "remote"
                root = os.path.dirname(fname).split("/")[0] if "/" in fname else "remote"
                found.append(
                    {
                        "label": f"{parent}  [hf:{repo}]",
                        "path": local_path,
                        "experiment": parent,
                        "root": root,
                    }
                )
        except Exception as e:
            print(f"[WARN] Could not discover remote checkpoints from {repo}: {e}")
    return found


def checkpoint_map():
    return {item["label"]: item for item in discover_checkpoints()}


def default_checkpoint_label():
    cps = discover_checkpoints()
    if not cps:
        return None
    for item in cps:
        if item["path"].endswith("ablation_results/T4/best_model.pt"):
            return item["label"]
    return cps[0]["label"]


def infer_model_type(experiment_name: str, root: str = "") -> str:
    if root == "ablation_results":
        return "d3pm_cross_attention"
    if experiment_name.startswith("d3pm_cross_attention"):
        return "d3pm_cross_attention"
    if experiment_name.startswith("d3pm_encoder_decoder"):
        return "d3pm_encoder_decoder"
    if experiment_name.startswith("baseline_cross_attention"):
        return "baseline_cross_attention"
    if experiment_name.startswith("baseline_encoder_decoder"):
        return "baseline_encoder_decoder"
    return CONFIG["model_type"]


def infer_include_negative(experiment_name: str, root: str = "") -> bool:
    if root == "ablation_results":
        return False
    if "_neg_True" in experiment_name:
        return True
    if "_neg_False" in experiment_name:
        return False
    return CONFIG["data"]["include_negative_examples"]


def build_runtime_cfg(ckpt_path: str):
    experiment = os.path.basename(os.path.dirname(ckpt_path)) or "remote"
    root = os.path.basename(os.path.dirname(os.path.dirname(ckpt_path))) or "remote"
    cfg = copy.deepcopy(CONFIG)
    cfg["model_type"] = infer_model_type(experiment, root=root)
    cfg["data"]["include_negative_examples"] = infer_include_negative(experiment, root=root)

    if root == "ablation_results" and experiment.startswith("T") and experiment[1:].isdigit():
        t_val = int(experiment[1:])
        cfg["model"]["diffusion_steps"] = t_val
        cfg["inference"]["num_steps"] = t_val

    device = _resolve_device(cfg)
    return cfg, device, experiment


def load_selected_model(checkpoint_label):
    mapping = checkpoint_map()
    if checkpoint_label not in mapping:
        raise gr.Error("Selected checkpoint not found. Click refresh.")

    ckpt_path = mapping[checkpoint_label]["path"]
    cfg, device, experiment = build_runtime_cfg(ckpt_path)
    model, cfg = load_model(ckpt_path, cfg, device)
    src_tok, tgt_tok = _build_tokenizers(cfg)

    bundle = {
        "ckpt_path": ckpt_path,
        "experiment": experiment,
        "device": str(device),
        "cfg": cfg,
        "model": model,
        "src_tok": src_tok,
        "tgt_tok": tgt_tok,
    }
    MODEL_CACHE[checkpoint_label] = bundle
    model_info = {
        "checkpoint": ckpt_path,
        "experiment": experiment,
        "model_type": cfg["model_type"],
        "include_negatives": cfg["data"]["include_negative_examples"],
        "device": str(device),
        "max_seq_len": cfg["model"]["max_seq_len"],
        "diffusion_steps": cfg["model"]["diffusion_steps"],
        "inference_steps": cfg["inference"]["num_steps"],
        "d_model": cfg["model"]["d_model"],
        "n_layers": cfg["model"]["n_layers"],
        "n_heads": cfg["model"]["n_heads"],
    }
    status = f"Loaded `{experiment}` on `{device}` (`{cfg['model_type']}`)"
    suggested_out = os.path.join("analysis", "outputs_ui", experiment)
    return checkpoint_label, status, json.dumps(model_info, ensure_ascii=False, indent=2), cfg["inference"]["num_steps"], suggested_out


def _get_bundle(model_key: str):
    if not model_key:
        raise gr.Error("Load a model first.")
    if model_key not in MODEL_CACHE:
        mapping = checkpoint_map()
        if model_key not in mapping:
            raise gr.Error("Selected checkpoint is no longer available. Refresh and load again.")
        # Lazy reload if Space process restarted.
        load_selected_model(model_key)
    return MODEL_CACHE[model_key]


def apply_preset(preset_name):
    presets = {
        "Manual": (0.70, 40, 1.20, 0.0),
        "Literal": (0.60, 20, 1.25, 0.0),
        "Balanced": (0.70, 40, 1.20, 0.0),
        "Creative": (0.90, 80, 1.05, 0.2),
    }
    return presets.get(preset_name, presets["Balanced"])


def clean_generated_text(text: str, max_consecutive: int = 2) -> str:
    text = " ".join(text.split())
    if not text:
        return text
    tokens = text.split()
    cleaned = []
    prev = None
    run = 0
    for tok in tokens:
        if tok == prev:
            run += 1
        else:
            prev = tok
            run = 1
        if run <= max_consecutive:
            cleaned.append(tok)
    out = " ".join(cleaned).replace(" ।", "।").replace(" ॥", "॥")
    return " ".join(out.split())


def save_generation(experiment, record):
    ts = datetime.now().strftime("%Y%m%d")
    path = os.path.join(RESULTS_DIR, f"{experiment}_ui_{ts}.json")
    existing = []
    if os.path.exists(path):
        with open(path, "r", encoding="utf-8") as f:
            existing = json.load(f)
    existing.append(record)
    with open(path, "w", encoding="utf-8") as f:
        json.dump(existing, f, ensure_ascii=False, indent=2)
    return path


def generate_from_ui(
    model_key,
    input_text,
    temperature,
    top_k,
    repetition_penalty,
    diversity_penalty,
    num_steps,
    clean_output,
):
    model_bundle = _get_bundle(model_key)
    if not input_text.strip():
        raise gr.Error("Enter input text first.")

    cfg = copy.deepcopy(model_bundle["cfg"])
    cfg["inference"]["temperature"] = float(temperature)
    cfg["inference"]["top_k"] = int(top_k)
    cfg["inference"]["repetition_penalty"] = float(repetition_penalty)
    cfg["inference"]["diversity_penalty"] = float(diversity_penalty)
    cfg["inference"]["num_steps"] = int(num_steps)

    src_tok = model_bundle["src_tok"]
    tgt_tok = model_bundle["tgt_tok"]
    device = torch.device(model_bundle["device"])

    input_ids = torch.tensor([src_tok.encode(input_text.strip())], dtype=torch.long, device=device)
    out = run_inference(model_bundle["model"], input_ids, cfg)

    # Align decode with validation style: strip only special ids.
    pad_id = 1
    mask_id = cfg["diffusion"]["mask_token_id"]
    decoded_ids = [x for x in out[0].tolist() if x not in (pad_id, mask_id)]
    raw_output_text = tgt_tok.decode(decoded_ids).strip()
    output_text = clean_generated_text(raw_output_text) if clean_output else raw_output_text
    if not output_text:
        output_text = "(empty output)"

    record = {
        "timestamp": datetime.now().isoformat(timespec="seconds"),
        "experiment": model_bundle["experiment"],
        "checkpoint": model_bundle["ckpt_path"],
        "input_text": input_text,
        "raw_output_text": raw_output_text,
        "output_text": output_text,
        "temperature": float(temperature),
        "top_k": int(top_k),
        "repetition_penalty": float(repetition_penalty),
        "diversity_penalty": float(diversity_penalty),
        "num_steps": int(num_steps),
        "clean_output": bool(clean_output),
    }
    log_path = save_generation(model_bundle["experiment"], record)
    status = f"Inference done. Saved: `{log_path}`"
    return output_text, status, json.dumps(record, ensure_ascii=False, indent=2)


def _run_analysis_cmd(task, ckpt_path, output_dir, input_text="dharmo rakṣati rakṣitaḥ", phase="analyze"):
    os.makedirs(output_dir, exist_ok=True)
    cmd = [
        sys.executable,
        "analysis/run_analysis.py",
        "--task",
        str(task),
        "--checkpoint",
        ckpt_path,
        "--output_dir",
        output_dir,
    ]
    if str(task) == "2" or str(task) == "all":
        cmd.extend(["--input", input_text])
    if str(task) == "4":
        cmd.extend(["--phase", phase])

    env = os.environ.copy()
    env.setdefault("HF_HOME", "/tmp/hf_home")
    env.setdefault("HF_DATASETS_CACHE", "/tmp/hf_datasets")
    env.setdefault("HF_HUB_CACHE", "/tmp/hf_hub")

    proc = subprocess.run(cmd, capture_output=True, text=True, env=env)
    log = f"$ {' '.join(cmd)}\n\n{proc.stdout}\n{proc.stderr}"
    return proc.returncode, log


def run_single_task(model_key, task, output_dir, input_text, task4_phase):
    model_bundle = _get_bundle(model_key)
    code, log = _run_analysis_cmd(task, model_bundle["ckpt_path"], output_dir, input_text, task4_phase)
    status = f"Task {task} {'completed' if code == 0 else 'failed'} (exit={code})."
    return status, log


def run_all_tasks(model_key, output_dir, input_text, task4_phase):
    model_bundle = _get_bundle(model_key)
    logs = []
    failures = 0
    for task in ["1", "2", "3", "4", "5"]:
        code, log = _run_analysis_cmd(task, model_bundle["ckpt_path"], output_dir, input_text, task4_phase)
        logs.append(f"\n\n{'='*22} TASK {task} {'='*22}\n{log}")
        if code != 0:
            failures += 1
    status = f"Run-all finished with {failures} failed task(s)." if failures else "All 5 tasks completed."
    return status, "".join(logs)


def _read_text(path):
    if not os.path.exists(path):
        return "Not found."
    with open(path, "r", encoding="utf-8", errors="ignore") as f:
        return f.read()


def _img_or_none(path):
    return path if os.path.exists(path) else None


def refresh_task_outputs(output_dir):
    task1_txt = _read_text(os.path.join(output_dir, "task1_kv_cache.txt"))
    task2_txt = _read_text(os.path.join(output_dir, "task2_report.txt"))
    task3_txt = _read_text(os.path.join(output_dir, "task3_report.txt"))
    task5_txt = _read_text(os.path.join(output_dir, "task5_report.txt"))

    task2_drift = _img_or_none(os.path.join(output_dir, "task2_semantic_drift.png"))
    task2_attn = _img_or_none(os.path.join(output_dir, "task2_attn_t0.png"))
    task3_space = _img_or_none(os.path.join(output_dir, "task3_concept_space.png"))
    task4_plot = _img_or_none(os.path.join(output_dir, "task4_ablation_3d.png"))
    return task1_txt, task2_txt, task2_drift, task2_attn, task3_txt, task3_space, task5_txt, task4_plot


CUSTOM_CSS = """
:root {
  --bg1: #f5fbff;
  --bg2: #f2f7ef;
  --card: #ffffff;
  --line: #d9e6f2;
  --ink: #163048;
}
.gradio-container {
  background: linear-gradient(130deg, var(--bg1), var(--bg2));
  color: var(--ink);
}
#hero {
  background: radial-gradient(110% 130% at 0% 0%, #d7ebff 0%, #ecf6ff 55%, #f8fbff 100%);
  border: 1px solid #cfe0f1;
  border-radius: 16px;
  padding: 18px 20px;
}
.panel {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
}
"""


with gr.Blocks(title="Sanskrit Diffusion Client Demo", css=CUSTOM_CSS) as demo:
    model_state = gr.State("")

    gr.Markdown(
        """
<div id="hero">
  <h1 style="margin:0;">Sanskrit Diffusion Client Demo</h1>
  <p style="margin:.5rem 0 0 0;">
    Select any trained model, run all 5 analysis tasks or individual tasks, then test inference with user-controlled parameters.
  </p>
</div>
"""
    )

    with gr.Row():
        with gr.Column(scale=2, elem_classes=["panel"]):
            checkpoint_dropdown = gr.Dropdown(
                label="Model Checkpoint",
                choices=list(checkpoint_map().keys()),
                value=default_checkpoint_label(),
                interactive=True,
            )
        with gr.Column(scale=1, elem_classes=["panel"]):
            refresh_btn = gr.Button("Refresh Models")
            load_btn = gr.Button("Load Selected Model", variant="primary")

    load_status = gr.Markdown("Select a model and load.")
    model_info = gr.Textbox(label="Loaded Model Details (JSON)", lines=12, interactive=False)

    with gr.Tabs():
        with gr.Tab("1) Task Runner"):
            with gr.Row():
                with gr.Column(scale=2):
                    analysis_output_dir = gr.Textbox(
                        label="Analysis Output Directory",
                        value=DEFAULT_ANALYSIS_OUT,
                    )
                    analysis_input = gr.Textbox(
                        label="Task 2 Input Text",
                        value="dharmo rakṣati rakṣitaḥ",
                        lines=2,
                    )
                with gr.Column(scale=1):
                    task4_phase = gr.Dropdown(
                        choices=["analyze", "generate_configs"],
                        value="analyze",
                        label="Task 4 Phase",
                    )
                    run_all_btn = gr.Button("Run All 5 Tasks", variant="primary")

            with gr.Row():
                task_choice = gr.Dropdown(
                    choices=["1", "2", "3", "4", "5"],
                    value="1",
                    label="Single Task",
                )
                run_single_btn = gr.Button("Run Selected Task")
                refresh_outputs_btn = gr.Button("Refresh Output Viewer")

            task_run_status = gr.Markdown("")
            task_run_log = gr.Textbox(label="Task Execution Log", lines=18, interactive=False)

            with gr.Accordion("Task Outputs Viewer", open=True):
                task1_box = gr.Textbox(label="Task 1 Report", lines=10, interactive=False)
                task2_box = gr.Textbox(label="Task 2 Report", lines=10, interactive=False)
                with gr.Row():
                    task2_drift_img = gr.Image(label="Task2 Drift", type="filepath")
                    task2_attn_img = gr.Image(label="Task2 Attention", type="filepath")
                task3_box = gr.Textbox(label="Task 3 Report", lines=10, interactive=False)
                task3_img = gr.Image(label="Task3 Concept Space", type="filepath")
                task5_box = gr.Textbox(label="Task 5 Report", lines=10, interactive=False)
                task4_img = gr.Image(label="Task4 3D Ablation Plot", type="filepath")

        with gr.Tab("2) Inference Playground"):
            with gr.Row():
                with gr.Column(scale=2):
                    input_text = gr.Textbox(
                        label="Input (Roman / IAST)",
                        lines=4,
                        value="dharmo rakṣati rakṣitaḥ",
                    )
                    output_text = gr.Textbox(
                        label="Output (Devanagari)",
                        lines=7,
                        interactive=False,
                    )
                    run_status = gr.Markdown("")
                    run_record = gr.Textbox(label="Inference Metadata (JSON)", lines=12, interactive=False)
                with gr.Column(scale=1, elem_classes=["panel"]):
                    preset = gr.Radio(["Manual", "Literal", "Balanced", "Creative"], value="Balanced", label="Preset")
                    temperature = gr.Slider(0.4, 1.2, value=0.70, step=0.05, label="Temperature")
                    top_k = gr.Slider(5, 100, value=40, step=1, label="Top-K")
                    repetition_penalty = gr.Slider(1.0, 3.0, value=1.20, step=0.05, label="Repetition Penalty")
                    diversity_penalty = gr.Slider(0.0, 1.0, value=0.0, step=0.05, label="Diversity Penalty")
                    num_steps = gr.Slider(1, 128, value=64, step=1, label="Inference Steps")
                    clean_output = gr.Checkbox(value=True, label="Clean Output")
                    generate_btn = gr.Button("Generate", variant="primary")

            gr.Examples(
                examples=[
                    ["dharmo rakṣati rakṣitaḥ"],
                    ["satyameva jayate"],
                    ["yadā mano nivarteta viṣayebhyaḥ svabhāvataḥ"],
                ],
                inputs=[input_text],
            )

    def refresh_checkpoints():
        choices = list(checkpoint_map().keys())
        value = default_checkpoint_label() if choices else None
        return gr.update(choices=choices, value=value)

    refresh_btn.click(fn=refresh_checkpoints, outputs=[checkpoint_dropdown])
    load_btn.click(
        fn=load_selected_model,
        inputs=[checkpoint_dropdown],
        outputs=[model_state, load_status, model_info, num_steps, analysis_output_dir],
    )

    preset.change(
        fn=apply_preset,
        inputs=[preset],
        outputs=[temperature, top_k, repetition_penalty, diversity_penalty],
    )

    generate_btn.click(
        fn=generate_from_ui,
        inputs=[
            model_state,
            input_text,
            temperature,
            top_k,
            repetition_penalty,
            diversity_penalty,
            num_steps,
            clean_output,
        ],
        outputs=[output_text, run_status, run_record],
    )
    input_text.submit(
        fn=generate_from_ui,
        inputs=[
            model_state,
            input_text,
            temperature,
            top_k,
            repetition_penalty,
            diversity_penalty,
            num_steps,
            clean_output,
        ],
        outputs=[output_text, run_status, run_record],
    )

    run_single_btn.click(
        fn=run_single_task,
        inputs=[model_state, task_choice, analysis_output_dir, analysis_input, task4_phase],
        outputs=[task_run_status, task_run_log],
    )
    run_all_btn.click(
        fn=run_all_tasks,
        inputs=[model_state, analysis_output_dir, analysis_input, task4_phase],
        outputs=[task_run_status, task_run_log],
    )
    refresh_outputs_btn.click(
        fn=refresh_task_outputs,
        inputs=[analysis_output_dir],
        outputs=[
            task1_box,
            task2_box,
            task2_drift_img,
            task2_attn_img,
            task3_box,
            task3_img,
            task5_box,
            task4_img,
        ],
    )
    demo.load(
        fn=refresh_task_outputs,
        inputs=[analysis_output_dir],
        outputs=[
            task1_box,
            task2_box,
            task2_drift_img,
            task2_attn_img,
            task3_box,
            task3_img,
            task5_box,
            task4_img,
        ],
    )


if __name__ == "__main__":
    port = int(os.environ["GRADIO_SERVER_PORT"]) if "GRADIO_SERVER_PORT" in os.environ else None
    demo.launch(server_name="0.0.0.0", server_port=port, share=False, show_api=False)