package syncer

// 两阶段编排器：快照（飞书→镜像）与物化（镜像→LLDAP）。
//
// 这两段共享一把单实例互斥锁，保证快照与物化绝不同时执行（镜像事务化 + 物化
// 全成功才回写的前提），否则物化可能读到半新半旧的镜像污染 LDAP（约束 2）。

import (
	"context"
	"fmt"
	"log/slog"
	"strings"
	"sync"

	"idsync/internal/config"
	"idsync/internal/feishu"
	"idsync/internal/ldaplib"
	"idsync/internal/lldapgql"
	"idsync/internal/mapping"
	"idsync/internal/store"
)

// Runner 编排快照与物化。
type Runner struct {
	cfg      *config.Config
	feishu   *feishu.Client
	ldap     *ldaplib.Client
	gql      *lldapgql.Client
	store    *store.Store
	snapshot *SnapshotRunner
	log      *slog.Logger

	guard Guard
	// mu 让快照与物化在单实例内互斥。
	mu       sync.Mutex
	groupIDs map[string]int
}

// NewRunner 构造编排器。
func NewRunner(cfg *config.Config, f *feishu.Client, l *ldaplib.Client, g *lldapgql.Client,
	s *store.Store, log *slog.Logger, opts SnapshotOptions) *Runner {
	return &Runner{
		cfg:      cfg,
		feishu:   f,
		ldap:     l,
		gql:      g,
		store:    s,
		snapshot: NewSnapshotRunner(cfg, f, s, log, opts),
		log:      log,
		guard: Guard{
			MaxDeactivate:        cfg.Guard.MaxDeactivate,
			MaxDeactivatePercent: cfg.Guard.MaxDeactivatePercent,
		},
	}
}

// RunSnapshot 触发一轮快照（飞书 → 镜像 + 离职流程推进）。
func (r *Runner) RunSnapshot(ctx context.Context) (*SnapshotRunResult, error) {
	r.mu.Lock()
	defer r.mu.Unlock()
	return r.snapshot.RunSnapshot(ctx)
}

// Preview 只计算物化计划，不做任何写入。dry-run 与真正执行共用同一份计划代码。
func (r *Runner) Preview(ctx context.Context) (*Plan, error) {
	plan, _, err := r.plan(ctx)
	return plan, err
}

// Run 执行一轮物化（镜像 → LLDAP）。dryRun 为 true 时只计算并返回计划。
func (r *Runner) Run(ctx context.Context, dryRun bool, force bool, trigger string) (*Plan, *Result, error) {
	r.mu.Lock()
	defer r.mu.Unlock()

	run, err := r.store.StartRun(modeOf(dryRun), trigger)
	if err != nil {
		return nil, nil, fmt.Errorf("创建物化记录失败: %w", err)
	}

	plan, desired, err := r.prepare(ctx, run, force)
	if err != nil {
		return plan, nil, err
	}
	if dryRun {
		fillRunFromPlan(run, plan)
		run.Status = "success"
		if err := r.store.FinishRun(run); err != nil {
			r.log.Warn("写入物化记录失败", "err", err)
		}
		return plan, nil, nil
	}

	res := r.apply(ctx, plan)
	fillRunFromResult(run, plan, res)

	// 只有全部成功才回写镜像：部分失败时保持镜像不变，下轮重算差异。
	if res.Failed == 0 {
		if err := r.persist(ctx, plan, desired); err != nil {
			run.Status = "failed"
			run.ErrorMsg = "回写镜像失败: " + err.Error()
			_ = r.store.FinishRun(run)
			return plan, res, fmt.Errorf("回写镜像失败: %w", err)
		}
	} else {
		r.log.Warn("存在失败的操作，跳过镜像回写", "failed", res.Failed)
	}

	run.Status = "success"
	if res.Failed > 0 {
		run.Status = "failed"
		run.ErrorMsg = strings.Join(res.Errors, "; ")
	}
	if err := r.store.FinishRun(run); err != nil {
		r.log.Warn("写入物化记录失败", "err", err)
	}

	return plan, res, nil
}

// prepare 计算计划并做安全检查。
func (r *Runner) prepare(ctx context.Context, run *store.SyncRun, force bool) (*Plan, *mapping.DesiredState, error) {
	plan, desired, err := r.plan(ctx)
	if err != nil {
		run.Status = "failed"
		run.ErrorMsg = err.Error()
		_ = r.store.FinishRun(run)
		return nil, nil, err
	}

	guard := r.guard
	if force {
		guard.AllowBulk = true
	}
	if err := guard.Check(plan); err != nil {
		run.Status = "failed"
		run.ErrorMsg = err.Error()
		_ = r.store.FinishRun(run)
		return plan, desired, err
	}
	return plan, desired, nil
}

// plan 读两侧状态并计算物化计划。
func (r *Runner) plan(ctx context.Context) (*Plan, *mapping.DesiredState, error) {
	// 期望侧：只读 SQLite 镜像的 active 视图，不碰飞书。
	activeUsers, err := r.store.ActiveUsers()
	if err != nil {
		return nil, nil, err
	}
	depts, err := r.store.ActiveDepartments()
	if err != nil {
		return nil, nil, err
	}
	desired := mapping.BuildFromMirror(activeUsers, depts, r.cfg.Ldap.BaseDN)

	// 实际侧：读 LLDAP 的 LDAP 视图。
	conn, err := r.ldap.Dial()
	if err != nil {
		return nil, nil, err
	}
	defer conn.Close()

	actualUsers, err := conn.ListUsers(r.cfg.UserOUDN())
	if err != nil {
		return nil, nil, err
	}
	actualGroups, err := conn.ListGroups(r.cfg.GroupRootDN())
	if err != nil {
		return nil, nil, err
	}

	// 所有权与删除白名单都来自镜像台账。
	all, err := r.store.AllMirrorUsers()
	if err != nil {
		return nil, nil, err
	}
	owned := make(map[string]struct{}, len(all))
	confirmed := make(map[string]bool)
	for _, u := range all {
		if u.Skipped {
			continue
		}
		owned[u.UID] = struct{}{}
		if u.State == store.StateConfirmedLeave {
			confirmed[u.UID] = true
		}
	}

	plan := ComputePlan(&Input{
		Desired:        desired,
		ActualUsers:    actualUsers,
		ActualGroups:   actualGroups,
		OwnedUsers:     owned,
		ConfirmedLeave: confirmed,
		AdminDN:        r.cfg.Ldap.AdminDN,
		PeopleOU:       r.cfg.UserOUDN(),
		GroupRootDN:    r.cfg.GroupRootDN(),
	})
	return plan, desired, nil
}

// apply 通过 GraphQL 执行计划。每次物化开始时登录一次，并拉全量组建立 dept_id→groupId 映射。
func (r *Runner) apply(ctx context.Context, plan *Plan) *Result {
	if err := r.gql.Login(ctx, r.cfg.Lldap.AdminUser, r.cfg.Lldap.AdminPass); err != nil {
		return &Result{Failed: 1, Errors: []string{err.Error()}}
	}
	groups, err := r.gql.Groups(ctx)
	if err != nil {
		return &Result{Failed: 1, Errors: []string{err.Error()}}
	}
	groupIDs := make(map[string]int, len(groups))
	for _, g := range groups {
		groupIDs[g.DisplayName] = g.ID
	}

	exec := NewExecutor(r.gql, ExecConfig{PeopleOU: r.cfg.UserOUDN()}, r.log)
	res := exec.Apply(ctx, plan, groupIDs)
	r.groupIDs = groupIDs
	return res
}

// persist 在物化全部成功后回写镜像：用户 attrs_hash、部门 groupId、被删用户标记 deleted。
func (r *Runner) persist(ctx context.Context, plan *Plan, desired *mapping.DesiredState) error {
	for _, u := range desired.Users {
		if err := r.store.SetUserAttrsHash(u.UID, AttrsHash(u)); err != nil {
			return err
		}
	}
	for deptID, gid := range r.groupIDs {
		if err := r.store.SetDeptGroupID(deptID, gid); err != nil {
			return err
		}
	}
	for _, op := range plan.Ops {
		if op.Kind == OpDeleteUser {
			if err := r.store.MarkDeleted(op.Target); err != nil {
				return err
			}
		}
	}
	return nil
}

// modeOf 把 dry-run 标志转成记录用的模式名。
func modeOf(dryRun bool) string {
	if dryRun {
		return "dry-run"
	}
	return "apply"
}

// fillRunFromPlan 用计划统计填充物化记录（dry-run 时使用）。
func fillRunFromPlan(run *store.SyncRun, plan *Plan) {
	run.Created = plan.Stats.CreateUser + plan.Stats.CreateGroup
	run.Updated = plan.Stats.UpdateUser
	run.Added = plan.Stats.AddMember
	run.Removed = plan.Stats.RemoveMember
	run.Skipped = plan.Stats.Unchanged
}

// fillRunFromResult 用实际执行结果填充物化记录。
func fillRunFromResult(run *store.SyncRun, plan *Plan, res *Result) {
	run.Created = res.Created
	run.Updated = res.Updated
	run.Added = res.Added
	run.Removed = res.Removed
	run.Failed = res.Failed
	run.Skipped = plan.Stats.Unchanged
}