"""Append-only trace event log for live UI updates.

Tool call args/results are captured by wrapping LiteForge tool callables.
LiteForge's agent history only exposes step kinds, not tool I/O.
"""
from __future__ import annotations

import json
import re
from dataclasses import dataclass, field
from typing import Any, Literal

TraceKind = Literal["tool_call", "tool_result", "tier_escalation", "final", "error"]

_REDACTED = "[REDACTED]"
_PREFIXES = ("sk-", "ghp_", "gho_", "ghs_", "github_pat_", "xoxb-", "xoxp-", "AKIA", "AIza", "glpat-")
_SENSITIVE_KEYS = (
    "api_key", "apikey", "token", "secret", "password", "passwd",
    "access_key", "client_secret", "private_key",
)


@dataclass
class TraceEvent:
    kind: TraceKind
    name: str
    detail: str
    step: int | None = None
    duration_ms: int | None = None
    tokens: int | None = None


@dataclass
class TraceCollector:
    """Thread-safe enough for asyncio single-task agent runs."""

    events: list[TraceEvent] = field(default_factory=list)
    _tool_step: int = 0

    def record(self, kind: TraceKind, name: str, detail: str, **meta) -> None:
        self.events.append(TraceEvent(kind=kind, name=name, detail=detail, **meta))

    def record_tool_call(self, name: str, args: dict[str, Any]) -> None:
        self.record("tool_call", name, _format_payload(args), step=self._tool_step)

    def record_tool_result(self, name: str, result: dict[str, Any]) -> None:
        self.record("tool_result", name, _format_payload(result), step=self._tool_step)
        self._tool_step += 1

    def record_escalation(self, from_tier: str, to_tier: str) -> None:
        self.record("tier_escalation", to_tier, f"escalated from {from_tier}")

    def record_final(self, text: str) -> None:
        self.record("final", "response", redact(text))

    def record_error(self, text: str) -> None:
        self.record("error", "error", redact(text))

    def snapshot(self) -> list[TraceEvent]:
        return list(self.events)


def redact(text: str) -> str:
    """Conservative secret redaction for UI display."""
    lines = []
    for line in text.splitlines(keepends=True):
        content, nl = (line[:-1], "\n") if line.endswith("\n") else (line, "")
        lines.append(_redact_line(content) + nl)
    return "".join(lines)


def _redact_line(line: str) -> str:
    out: list[str] = []
    i = 0
    while i < len(line):
        ch = line[i]
        if ch in "\"'`" or ch.isalnum() or ch in "_-":
            j = i
            while j < len(line) and not line[j].isspace() and line[j] not in ",;)]}":
                j += 1
            token = line[i:j]
            if _looks_secret(token):
                out.append(_REDACTED)
            else:
                out.append(token)
            i = j
            continue
        if ch == "=" and i + 1 < len(line):
            key_start = i
            while key_start > 0 and (line[key_start - 1].isalnum() or line[key_start - 1] in "_-"):
                key_start -= 1
            key = line[key_start:i].lower()
            if any(s in key for s in _SENSITIVE_KEYS):
                out.append(line[i : i + 1])
                i += 1
                j = i
                while j < len(line) and not line[j].isspace():
                    j += 1
                out.append(_REDACTED)
                i = j
                continue
        out.append(ch)
        i += 1
    return "".join(out)


def _looks_secret(token: str) -> bool:
    for prefix in _PREFIXES:
        if token.startswith(prefix) and len(token) >= len(prefix) + 8:
            return True
    if len(token) >= 32 and re.fullmatch(r"[A-Za-z0-9_\-+/=]+", token):
        upper = sum(1 for c in token if c.isupper())
        lower = sum(1 for c in token if c.islower())
        digit = sum(1 for c in token if c.isdigit())
        if upper >= 4 and lower >= 4 and digit >= 2:
            return True
    return False


def _format_payload(data: dict[str, Any], *, max_content: int = 600) -> str:
    """JSON-format tool args/results, truncating large file content."""
    out = dict(data)
    if "content" in out and isinstance(out["content"], str):
        text = out["content"]
        if len(text) > max_content:
            out["content"] = text[:max_content] + f"\n… ({len(text)} chars total)"
    raw = json.dumps(out, indent=2, ensure_ascii=False)
    return redact(raw)