import logging
from datetime import datetime, timezone

from fastapi import APIRouter, HTTPException
from fastapi.responses import JSONResponse

from app.core.dependencies import get_prompt_service
from app.models.prompts import (
    ProfileListResponse,
    ProfileItem,
    PromptSetResponse,
    PromptUpdateRequest,
    PromptBatchUpdateRequest,
    ResetToDefaultsRequest,
    ProfileExportResponse,
    AllProfilesExportResponse,
    ProfileImportRequest,
    ProfileImportResponse,
)

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/v1/prompts", tags=["prompts"])

_VALID_NAMES = {"A", "B", "C"}
_VALID_STEPS = {
    "decompose",
    "filter",
    "generate",
    "generate_per_subq",
    "filter_intro",
    "filter_section",
    "filter_outro",
}


def _ensure_valid_name(name: str) -> None:
    if name not in _VALID_NAMES:
        raise HTTPException(status_code=400, detail=f"Invalid profile name '{name}'. Must be one of A, B, C.")


def _ensure_valid_step(step: str) -> None:
    if step not in _VALID_STEPS:
        raise HTTPException(status_code=400, detail=f"Invalid step '{step}'. Must be one of decompose, filter, generate.")


_EXPORT_FORMAT = "legco-reranker-profile/v1"


@router.get("/export/all", response_model=AllProfilesExportResponse)
def export_all_profiles():
    svc = get_prompt_service()
    profiles_list = svc.list_profiles()
    active_profile = svc.get_active_profile_name()
    profiles_data: dict[str, dict] = {}
    for p in profiles_list:
        profiles_data[p["name"]] = {"prompts": svc.get_profile_prompts(p["name"])}
    return AllProfilesExportResponse(
        format=_EXPORT_FORMAT,
        exported_at=datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ"),
        active_profile=active_profile,
        profiles=profiles_data,
    )


@router.get("/profiles/{name}/export", response_model=ProfileExportResponse)
def export_profile(name: str):
    _ensure_valid_name(name)
    svc = get_prompt_service()
    prompts = svc.get_profile_prompts(name)
    return JSONResponse(
        content=ProfileExportResponse(
            format=_EXPORT_FORMAT,
            profile_name=name,
            exported_at=datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ"),
            prompts=prompts,
        ).model_dump(),
        headers={"Content-Disposition": f'attachment; filename="legco-profile-{name}.json"'},
    )


@router.post("/profiles/{name}/import", response_model=ProfileImportResponse)
def import_profile(name: str, body: ProfileImportRequest):
    _ensure_valid_name(name)
    if body.format != _EXPORT_FORMAT:
        raise HTTPException(status_code=400, detail=f"Unsupported format '{body.format}'. Expected '{_EXPORT_FORMAT}'.")
    provided = set(body.prompts.keys())
    missing = _VALID_STEPS - provided
    if missing:
        raise HTTPException(status_code=400, detail=f"Missing required steps: {', '.join(sorted(missing))}")
    unknown = provided - _VALID_STEPS
    if unknown:
        raise HTTPException(status_code=400, detail=f"Unknown steps: {', '.join(sorted(unknown))}")
    svc = get_prompt_service()
    svc.update_all_prompts(name, body.prompts)
    return ProfileImportResponse(
        status="ok",
        profile=name,
        imported_steps=len(body.prompts),
        source_profile=body.profile_name,
    )


@router.get("/profiles", response_model=ProfileListResponse)
def list_profiles():
    svc = get_prompt_service()
    profiles = [ProfileItem(**p) for p in svc.list_profiles()]
    return ProfileListResponse(profiles=profiles)


@router.get("/profiles/{name}", response_model=PromptSetResponse)
def get_profile_prompts(name: str):
    _ensure_valid_name(name)
    svc = get_prompt_service()
    prompts = svc.get_profile_prompts(name)
    return PromptSetResponse(profile_name=name, prompts=prompts)


@router.put("/profiles/{name}/activate")
def activate_profile(name: str):
    _ensure_valid_name(name)
    svc = get_prompt_service()
    svc.activate_profile(name)
    return {"status": "ok", "active_profile": name}


@router.put("/profiles/{name}/all")
def update_all_prompts(name: str, body: PromptBatchUpdateRequest):
    _ensure_valid_name(name)
    svc = get_prompt_service()
    svc.update_all_prompts(name, body.prompts)
    return {"status": "ok", "profile": name}


@router.put("/profiles/{name}/reset")
def reset_to_defaults(name: str, body: ResetToDefaultsRequest | None = None):
    _ensure_valid_name(name)
    step = body.step if body else None
    if step is not None:
        _ensure_valid_step(step)
    svc = get_prompt_service()
    svc.reset_to_defaults(name, step=step)
    return {"status": "ok", "profile": name, "reset_step": step or "all"}


@router.put("/profiles/{name}/{step}")
def update_prompt(name: str, step: str, body: PromptUpdateRequest):
    _ensure_valid_name(name)
    _ensure_valid_step(step)
    svc = get_prompt_service()
    svc.update_prompt(name, step, body.template)
    return {"status": "ok", "profile": name, "step": step}