"""presets — format string → Quantizer kwargs.

Each preset maps a short format name to the kwargs that configure the unified
Quantizer for that specific quantization format.

Usage:
    q = Quantizer(**FORMAT_PRESETS["nvfp4"])
    # or via dispatch:
    quantize_model(model, format="nvfp4")
"""

from __future__ import annotations

FORMAT_PRESETS: dict[str, dict] = {
    # ---- Basic integer ----
    "int8": {
        "value_bits": 8, "value_repr": "int", "scale_mode": "per-channel",
    },
    "int4": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 64,
    },
    "int2": {
        "value_bits": 2, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 64,
    },
    "w4a16": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 128, "quantizes_input": False,
    },
    "w4a4": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 64, "quantizes_input": True,
    },
    "w8a8": {
        "value_bits": 8, "value_repr": "int", "scale_mode": "per-channel",
        "quantizes_input": True,
    },

    # ---- LUT / NF4 ----
    "nf4": {
        "value_bits": 4, "value_repr": "nf4_lut", "scale_mode": "per-group",
        "group_size": 64, "double_quant": True, "block_size": 256,
    },
    "nf4_dq": {
        "value_bits": 4, "value_repr": "nf4_lut", "scale_mode": "per-group",
        "group_size": 64, "double_quant": False,
    },

    # ---- FP4 / NVFP4 / MXFP4 ----
    "nvfp4": {
        "value_bits": 4, "value_repr": "fp4_e2m1", "scale_mode": "per-group",
        "scale_dtype": "fp8_e4m3", "group_size": 16, "quantizes_input": True,
    },
    "nvfp4_wo": {  # weight-only NVFP4
        "value_bits": 4, "value_repr": "fp4_e2m1", "scale_mode": "per-group",
        "scale_dtype": "fp8_e4m3", "group_size": 16, "quantizes_input": False,
    },
    "mxfp4": {
        "value_bits": 4, "value_repr": "fp4_e2m1", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },

    # ---- FP6 / MXFP6 / NVFP6 ----
    "mxfp6_e3m2": {
        "value_bits": 6, "value_repr": "fp6_e3m2", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },
    "mxfp6_e2m3": {
        "value_bits": 6, "value_repr": "fp6_e2m3", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },
    "nvfp6_e3m2": {
        "value_bits": 6, "value_repr": "fp6_e3m2", "scale_mode": "per-group",
        "scale_dtype": "fp8_e4m3", "group_size": 16,
    },
    "nvfp6_e2m3": {
        "value_bits": 6, "value_repr": "fp6_e2m3", "scale_mode": "per-group",
        "scale_dtype": "fp8_e4m3", "group_size": 16,
    },

    # ---- FP8 / MXFP8 / NVFP8 ----
    "fp8": {
        "value_bits": 8, "value_repr": "fp8_e4m3", "scale_mode": "per-channel",
    },
    "fp8_e5m2": {
        "value_bits": 8, "value_repr": "fp8_e5m2", "scale_mode": "per-channel",
    },
    "fp8_w8a8": {
        "value_bits": 8, "value_repr": "fp8_e4m3", "scale_mode": "per-channel",
        "quantizes_input": True,
    },
    "mxfp8_e4m3": {
        "value_bits": 8, "value_repr": "fp8_e4m3", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },
    "mxfp8_e5m2": {
        "value_bits": 8, "value_repr": "fp8_e5m2", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },
    "nvfp8_e4m3": {
        "value_bits": 8, "value_repr": "fp8_e4m3", "scale_mode": "per-group",
        "scale_dtype": "fp8_e4m3", "group_size": 16,
    },
    "nvfp8_e5m2": {
        "value_bits": 8, "value_repr": "fp8_e5m2", "scale_mode": "per-group",
        "scale_dtype": "fp8_e4m3", "group_size": 16,
    },

    # ---- MXINT (INT + E8M0 block scale) ----
    "mxint2": {
        "value_bits": 2, "value_repr": "int", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },
    "mxint4": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },
    "mxint6": {
        "value_bits": 6, "value_repr": "int", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },
    "mxint8": {
        "value_bits": 8, "value_repr": "int", "scale_mode": "per-group",
        "scale_dtype": "e8m0", "group_size": 32,
    },

    # ---- INT6 (plain integer, no block scale) ----
    "int6": {
        "value_bits": 6, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 64,
    },

    # ---- Ternary / Binary ----
    "ternary": {
        "value_bits": 2, "value_repr": "ternary", "scale_mode": "per-channel",
    },
    "binary": {
        "value_bits": 1, "value_repr": "binary", "scale_mode": "per-channel",
    },

    # ---- GGUF k-quants ----
    "q8_0": {
        "value_bits": 8, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 32,
    },
    "q4_0": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 32,
    },
    "q4_k": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_mode": "super-block-nested", "group_size": 256,
    },
    "q5_k": {
        "value_bits": 5, "value_repr": "int", "scale_mode": "per-group",
        "group_mode": "super-block-nested", "group_size": 256,
    },
    "q6_k": {
        "value_bits": 6, "value_repr": "int", "scale_mode": "per-group",
        "group_mode": "super-block-nested", "group_size": 256,
    },
    "q2_k": {
        "value_bits": 2, "value_repr": "int", "scale_mode": "per-group",
        "group_mode": "super-block-nested", "group_size": 256,
    },
    "q3_k": {
        "value_bits": 3, "value_repr": "int", "scale_mode": "per-group",
        "group_mode": "super-block-nested", "group_size": 256,
    },

    # ---- Advanced PTQ ----
    "gptq": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 0, "error_compensation": "gptq-hessian",
    },
    "awq": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_size": 128, "activation_aware": "awq",
    },
    "smoothquant": {
        "value_bits": 8, "value_repr": "int", "scale_mode": "per-channel",
        "activation_aware": "smoothquant", "alpha": 0.5, "quantizes_input": True,
    },
    "llmint8": {
        "value_bits": 8, "value_repr": "int", "scale_mode": "per-channel",
        "outlier_threshold": 6.0,
    },

    # ---- Codebook / VQ ----
    "codebook": {
        "value_repr": "codebook", "codebook_source": "kmeans",
        "codebook_size": 16, "scale_mode": "per-channel",
    },
    "vq": {
        "value_repr": "codebook", "codebook_source": "vq",
        "codebook_size": 256, "vq_group_size": 2, "scale_mode": "per-channel",
    },
    "aqlm": {
        "value_repr": "codebook", "codebook_source": "vq",
        "codebook_size": 256, "vq_group_size": 2, "scale_mode": "per-channel",
    },

    # ---- QuIP ----
    "quip": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-channel",
        "rotation": "random",
    },
    "quip_hadamard": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-channel",
        "rotation": "hadamard",
    },

    # ---- Outlier / Prune ----
    "outlier": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-channel",
        "outlier_threshold": None,  # auto 3σ
    },
    "outlier2": {
        "value_bits": 2, "value_repr": "int", "scale_mode": "per-channel",
        "outlier_threshold": None,
    },
    "prune": {
        "prune_mode": "ratio", "prune_ratio": 0.5,
    },
    "prune_structured": {
        "prune_mode": "structured", "prune_ratio": 0.25,
    },

    # ---- QAT ----
    "lsq": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-channel",
        "learnable": True,
    },

    # ---- Clustered (magnitude-binned) ----
    "clustered": {
        "value_bits": 4, "value_repr": "int", "scale_mode": "per-group",
        "group_mode": "magnitude-binned", "group_size": 64, "block_size": 4,
    },

    # ---- Passthrough ----
    "none": {
        "value_repr": "none",
    },
    "fp16": {
        "value_repr": "none",
    },
}


def get_preset(format: str, **overrides) -> dict:
    """Get preset kwargs, with optional overrides."""
    if format not in FORMAT_PRESETS:
        raise ValueError(f"Unknown format {format!r}. Available: {sorted(FORMAT_PRESETS)}")
    kwargs = dict(FORMAT_PRESETS[format])
    kwargs.update(overrides)
    return kwargs