# handlers/change_handler.py - 需求变更菜单处理
# 菜单 2 入口 / 操作 A 单条变更 / 操作 C 新增需求

from rich.console import Console
from rich.panel import Panel
from rich.prompt import Confirm, Prompt
from rich.rule import Rule
from rich.table import Table

from constants import CHG_ADD, CHG_EDIT
from core_utils import (
    active_reqs, generate_code, generate_signatures,
    log_change, merge_signatures_to_main,
    patch_and_save_signatures, write_readme,
)
from core.code_generator import CodeGenerator
from core.llm_client import LLMClient
from core.requirement_analyzer import RequirementAnalyzer
from database.db_manager import DBManager
from database.models import Project
from handlers.module_handler import change_module_requirements
from ui.display import (
    print_functional_requirements, print_module_summary,
    print_signatures_preview,
)
from ui.prompts import (
    load_knowledge_optional, pause, select_project,
)
from utils.output_writer import (
    ensure_project_dir, write_function_signatures_json,
)

console = Console()
db      = DBManager()


# ══════════════════════════════════════════════════════
#  菜单 2：变更项目需求（入口）
# ══════════════════════════════════════════════════════

def menu_change_requirements() -> None:
    console.print(Rule("[bold blue]变更项目需求[/bold blue]"))

    project = select_project("请选择要变更需求的项目 ID")
    if not project:
        return

    func_reqs = db.list_functional_requirements(project.id)
    if not active_reqs(func_reqs):
        console.print("[yellow]当前项目暂无功能需求。[/yellow]")
        pause()
        return

    output_dir     = ensure_project_dir(project.name)
    knowledge_text = load_knowledge_optional()

    change_menu = [
        ("A", "🔧 变更指定功能需求", "按需求 ID 修改单条需求"),
        ("B", "📦 变更指定模块需求", "按模块批量操作模块内所有需求"),
        ("C", "➕ 新增需求",         "输入新需求文本，LLM 分解后生成代码"),
    ]

    while True:
        console.print()
        print_functional_requirements(active_reqs(func_reqs))
        console.print(Rule("[bold]变更操作[/bold]"))

        table = Table(show_header=False, box=None, padding=(0, 2))
        table.add_column("选项", style="bold yellow", width=5)
        table.add_column("功能", style="bold",        width=22)
        table.add_column("说明", style="dim",         width=38)
        for key, name, desc in change_menu:
            table.add_row(f"[{key}]", name, desc)
        table.add_row("[back]", "↩  返回主菜单", "")
        console.print(table)

        action = Prompt.ask(
            "请选择操作", choices=["A", "B", "C", "back"], default="back",
        )

        if action == "A":
            change_existing_requirement(
                project=project, func_reqs=func_reqs,
                output_dir=output_dir, knowledge_text=knowledge_text,
            )
        elif action == "B":
            change_module_requirements(
                project=project, func_reqs=func_reqs,
                output_dir=output_dir, knowledge_text=knowledge_text,
            )
        elif action == "C":
            add_new_requirements(
                project=project, func_reqs=func_reqs,
                output_dir=output_dir, knowledge_text=knowledge_text,
            )
        else:
            break

        # 每次操作后刷新需求列表
        func_reqs = db.list_functional_requirements(project.id)

    pause()


# ══════════════════════════════════════════════════════
#  操作 A：变更指定功能需求（单条）
# ══════════════════════════════════════════════════════

def change_existing_requirement(
    project:        Project,
    func_reqs:      list,
    output_dir:     str,
    knowledge_text: str = "",
) -> None:
    """按需求 ID 修改单条功能需求，确认后重新生成签名与代码，记录变更历史。"""
    req_id_str = Prompt.ask("请输入要变更的功能需求 ID")
    try:
        req_id = int(req_id_str)
    except ValueError:
        console.print("[red]ID 必须为整数[/red]")
        return

    req = db.get_functional_requirement(req_id)
    if not req or req.project_id != project.id:
        console.print("[red]需求 ID 不存在或不属于当前项目[/red]")
        return
    if req.status == "deleted":
        console.print("[red]该需求已被删除，无法变更[/red]")
        return

    console.print(f"\n当前需求: [bold]{req.title}[/bold]（ID={req.id}）")
    new_description = Prompt.ask("  新描述",   default=req.description)
    new_priority    = Prompt.ask(
        "  新优先级", default=req.priority,
        choices=["high", "medium", "low"],
    )
    new_module = Prompt.ask("  新模块名", default=req.module)

    changed = (
        new_description != req.description
        or new_priority != req.priority
        or new_module   != req.module
    )
    if not changed:
        console.print("[dim]未检测到任何变更，跳过。[/dim]")
        return

    change_summary = (
        f"需求 '{req.title}'（ID={req.id}）变更：\n"
        f"  描述:   '{req.description}' → '{new_description}'\n"
        f"  优先级: '{req.priority}' → '{new_priority}'\n"
        f"  模块:   '{req.module}' → '{new_module}'"
    )
    console.print(Panel(change_summary, title="📝 变更预览", border_style="yellow"))

    if not Confirm.ask("确认执行以上变更？", default=True):
        console.print("[yellow]已取消变更。[/yellow]")
        return

    req.description = new_description
    req.priority    = new_priority
    req.module      = new_module
    req.status      = "pending"
    db.update_functional_requirement(req)

    log_change(
        project_id  = project.id,
        change_type = CHG_EDIT,
        summary     = change_summary,
        module      = new_module,
        req_id      = req.id,
    )
    console.print(f"[green]✓ 需求 ID={req.id} 已更新[/green]")

    console.print("\n[cyan]正在重新生成签名与代码...[/cyan]")
    llm             = LLMClient()
    analyzer        = RequirementAnalyzer(llm)
    generator       = CodeGenerator(llm)
    change_sig_file = f"change_{req.id}_signatures.json"

    signatures = generate_signatures(analyzer, [req], knowledge_text)
    write_function_signatures_json(
        output_dir=output_dir, signatures=signatures,
        project_name=project.name, project_description=project.description or "",
        file_name=change_sig_file,
    )
    print_signatures_preview(signatures)

    code_files = generate_code(
        generator=generator, project=project, func_reqs=[req],
        output_dir=output_dir, knowledge_text=knowledge_text, signatures=signatures,
    )
    for cf in code_files:
        db.upsert_code_file(cf)
    req.status = "generated"
    db.update_functional_requirement(req)

    patch_and_save_signatures(
        project=project, signatures=signatures, code_files=code_files,
        output_dir=output_dir, file_name=change_sig_file,
    )
    merge_signatures_to_main(project, signatures, output_dir)
    console.print(f"[green]✓ 变更完成，代码已重新生成[/green]")


# ══════════════════════════════════════════════════════
#  操作 C：新增需求
# ══════════════════════════════════════════════════════

def add_new_requirements(
    project:        Project,
    func_reqs:      list,
    output_dir:     str,
    knowledge_text: str = "",
) -> None:
    """输入新需求描述，LLM 分解后持久化并生成代码，记录变更历史。"""
    raw_reqs = db.get_raw_requirements_by_project(project.id)
    if not raw_reqs:
        console.print("[red]当前项目无原始需求记录，请先完成初始需求录入流程。[/red]")
        return
    raw_req_id = raw_reqs[0].id

    console.print("\n[bold]请输入新增需求描述[/bold]（输入空行结束）：")
    lines = []
    while True:
        line = input()
        if line == "":
            break
        lines.append(line)
    new_req_text = "\n".join(lines).strip()
    if not new_req_text:
        console.print("[yellow]新增需求内容为空，已取消。[/yellow]")
        return

    llm      = LLMClient()
    analyzer = RequirementAnalyzer(llm)

    with console.status("[cyan]LLM 正在分解新增需求...[/cyan]"):
        new_reqs = analyzer.add_new_requirements(
            new_requirement_text = new_req_text,
            project_id           = project.id,
            raw_req_id           = raw_req_id,
            existing_reqs        = active_reqs(func_reqs),
            knowledge            = knowledge_text,
        )

    console.print(f"[green]✓ 分解完成，新增 {len(new_reqs)} 条功能需求[/green]")
    print_functional_requirements(new_reqs)

    change_summary = (
        f"新增 {len(new_reqs)} 条功能需求：\n"
        + "\n".join(
            f"  + [{r.index_no}] {r.title} ({r.function_name})"
            for r in new_reqs
        )
    )
    console.print(Panel(change_summary, title="📝 新增需求预览", border_style="green"))

    if not Confirm.ask("确认新增以上需求并生成代码？", default=True):
        console.print("[yellow]已取消新增。[/yellow]")
        return

    # ── 模块分类 ──────────────────────────────────────
    with console.status("[cyan]LLM 正在进行模块分类...[/cyan]"):
        module_map = analyzer.classify_modules(new_reqs, knowledge_text)
    name_to_module = {item["function_name"]: item["module"] for item in module_map}
    for req in new_reqs:
        if req.function_name in name_to_module:
            req.module = name_to_module[req.function_name]
    print_module_summary(new_reqs)

    # ── 持久化新需求 ──────────────────────────────────
    all_reqs = db.list_functional_requirements(project.id)
    max_idx  = max((r.index_no for r in all_reqs), default=0)
    for i, req in enumerate(new_reqs):
        req.index_no = max_idx + i + 1
        req.id       = db.create_functional_requirement(req)
    console.print(f"[green]✓ 新增功能需求已持久化[/green]")

    # ── 记录变更历史 ──────────────────────────────────
    log_change(
        project_id  = project.id,
        change_type = CHG_ADD,
        summary     = change_summary,
    )

    # ── 生成签名与代码 ────────────────────────────────
    signatures = generate_signatures(analyzer, new_reqs, knowledge_text)
    write_function_signatures_json(
        output_dir=output_dir, signatures=signatures,
        project_name=project.name, project_description=project.description or "",
        file_name="function_signatures_new.json",
    )
    print_signatures_preview(signatures)

    generator  = CodeGenerator(llm)
    code_files = generate_code(
        generator=generator, project=project, func_reqs=new_reqs,
        output_dir=output_dir, knowledge_text=knowledge_text, signatures=signatures,
    )
    for cf in code_files:
        db.upsert_code_file(cf)
    for req in new_reqs:
        req.status = "generated"
        db.update_functional_requirement(req)

    patch_and_save_signatures(
        project=project, signatures=signatures, code_files=code_files,
        output_dir=output_dir, file_name="function_signatures_new.json",
    )
    merge_signatures_to_main(project, signatures, output_dir)

    # ── 更新 README ───────────────────────────────────
    all_active = active_reqs(db.list_functional_requirements(project.id))
    write_readme(project, all_active, output_dir)

    console.print(Panel.fit(
        f"[bold green]✅ 新增需求处理完成！[/bold green]\n"
        f"共生成 {len(code_files)} 个代码文件",
        border_style="green",
    ))