package mdb

import (
	"context"
	_ "embed"
	"fmt"
	"strconv"
	"strings"

	"zombiezen.com/go/sqlite"
	"zombiezen.com/go/sqlite/sqlitex"

	"git.sunturtle.xyz/zephyr/horse"
)

var (
	//go:embed sql/skill-group.sql
	skillGroupSQL string
	//go:embed sql/skill.sql
	skillSQL string
	//go:embed sql/skill-group-skills.sql
	skillGroupSkillsSQL string
)

// SkillGroups retrieves all skill groups.
func SkillGroups(ctx context.Context, db *sqlitex.Pool) ([]horse.SkillGroup, error) {
	return load(ctx, db, nil, skillGroupSQL, func(s *sqlite.Stmt) horse.SkillGroup {
		return horse.SkillGroup{
			ID:       horse.SkillGroupID(s.ColumnInt(0)),
			Skill1:   horse.SkillID(s.ColumnInt(1)),
			Skill2:   horse.SkillID(s.ColumnInt(2)),
			Skill3:   horse.SkillID(s.ColumnInt(3)),
			SkillBad: horse.SkillID(s.ColumnInt(4)),
		}
	})
}

// Skills retrieves all skills.
func Skills(ctx context.Context, db *sqlitex.Pool) ([]horse.Skill, error) {
	// We don't use func load here because we have multiple queries to run.
	conn, err := db.Take(ctx)
	defer db.Put(conn)
	if err != nil {
		return nil, err
	}
	var sk []horse.Skill
	{
		stmt := conn.Prep(skillSQL)
		defer stmt.Reset()
		for {
			ok, err := stmt.Step()
			if err != nil {
				return nil, err
			}
			if !ok {
				break
			}
			s := horse.Skill{
				ID:          horse.SkillID(stmt.ColumnInt(0)),
				Name:        stmt.ColumnText(1),
				Description: stmt.ColumnText(2),
				GroupSkills: make([]horse.GroupSkill, 0, 3),
				Group:       horse.SkillGroupID(stmt.ColumnInt32(3)),
				Rarity:      int8(stmt.ColumnInt(5)),
				GroupRate:   int8(stmt.ColumnInt(6)),
				GradeValue:  stmt.ColumnInt32(7),
				WitCheck:    stmt.ColumnBool(8),
				Activations: trimActivations([]horse.Activation{
					{
						Precondition: stmt.ColumnText(9),
						Condition:    stmt.ColumnText(10),
						Duration:     horse.TenThousandths(stmt.ColumnInt(11)),
						DurScale:     horse.DurScale(stmt.ColumnInt(12)),
						Cooldown:     horse.TenThousandths(stmt.ColumnInt(13)),
						Abilities: trimAbilities([]horse.Ability{
							{
								Type:        horse.AbilityType(stmt.ColumnInt(14)),
								ValueUsage:  horse.AbilityValueUsage(stmt.ColumnInt(15)),
								Value:       horse.TenThousandths(stmt.ColumnInt(16)),
								Target:      horse.AbilityTarget(stmt.ColumnInt(17)),
								TargetValue: stmt.ColumnInt32(18),
							},
							{
								Type:        horse.AbilityType(stmt.ColumnInt(19)),
								ValueUsage:  horse.AbilityValueUsage(stmt.ColumnInt(20)),
								Value:       horse.TenThousandths(stmt.ColumnInt(21)),
								Target:      horse.AbilityTarget(stmt.ColumnInt(22)),
								TargetValue: stmt.ColumnInt32(23),
							},
							{
								Type:        horse.AbilityType(stmt.ColumnInt(24)),
								ValueUsage:  horse.AbilityValueUsage(stmt.ColumnInt(25)),
								Value:       horse.TenThousandths(stmt.ColumnInt(26)),
								Target:      horse.AbilityTarget(stmt.ColumnInt(27)),
								TargetValue: stmt.ColumnInt32(28),
							},
						}),
					},
					{
						Precondition: stmt.ColumnText(29),
						Condition:    stmt.ColumnText(30),
						Duration:     horse.TenThousandths(stmt.ColumnInt(31)),
						DurScale:     horse.DurScale(stmt.ColumnInt(32)),
						Cooldown:     horse.TenThousandths(stmt.ColumnInt(33)),
						Abilities: trimAbilities([]horse.Ability{
							{
								Type:        horse.AbilityType(stmt.ColumnInt(34)),
								ValueUsage:  horse.AbilityValueUsage(stmt.ColumnInt(35)),
								Value:       horse.TenThousandths(stmt.ColumnInt(36)),
								Target:      horse.AbilityTarget(stmt.ColumnInt(37)),
								TargetValue: stmt.ColumnInt32(38),
							},
							{
								Type:        horse.AbilityType(stmt.ColumnInt(39)),
								ValueUsage:  horse.AbilityValueUsage(stmt.ColumnInt(40)),
								Value:       horse.TenThousandths(stmt.ColumnInt(41)),
								Target:      horse.AbilityTarget(stmt.ColumnInt(42)),
								TargetValue: stmt.ColumnInt32(43),
							},
							{
								Type:        horse.AbilityType(stmt.ColumnInt(44)),
								ValueUsage:  horse.AbilityValueUsage(stmt.ColumnInt(45)),
								Value:       horse.TenThousandths(stmt.ColumnInt(46)),
								Target:      horse.AbilityTarget(stmt.ColumnInt(47)),
								TargetValue: stmt.ColumnInt32(48),
							},
						}),
					},
				}),
				UniqueOwner: stmt.ColumnText(52), // TODO(zeph): should be id, not name
				Tags:        parseTags(stmt.ColumnText(54)),
				SPCost:      stmt.ColumnInt(49),
				IconID:      stmt.ColumnInt(53),
			}
			sk = append(sk, s)
		}
	}
	stmt := conn.Prep(skillGroupSkillsSQL)
	defer stmt.Reset()
	cur := sk
	for {
		ok, err := stmt.Step()
		if err != nil {
			return nil, err
		}
		if !ok {
			break
		}
		// We sort skills by ID first, so we can add group skills in a single pass.
		id := stmt.ColumnInt(0)
		for len(cur) != 0 && cur[0].ID != horse.SkillID(id) {
			cur = cur[1:]
		}
		g := horse.GroupSkill{
			ID:        horse.SkillID(stmt.ColumnInt(1)),
			GroupRate: int8(stmt.ColumnInt(2)),
			Rarity:    int8(stmt.ColumnInt(3)),
		}
		cur[0].GroupSkills = append(cur[0].GroupSkills, g)
	}
	return sk, nil
}

func parseTags(s string) []uint16 {
	r := make([]uint16, 0, 8)
	for s != "" {
		t, u, _ := strings.Cut(s, "/")
		s = u
		v, err := strconv.ParseUint(t, 10, 16)
		if err != nil {
			panic(fmt.Errorf("parsing skill tags: %w", err))
		}
		r = append(r, uint16(v))
	}
	return trimZeros(r...)
}

func trimAbilities(s []horse.Ability) []horse.Ability {
	for len(s) > 0 && s[len(s)-1].Type == 0 {
		s = s[:len(s)-1]
	}
	return s
}

func trimActivations(s []horse.Activation) []horse.Activation {
	for len(s) > 0 && s[len(s)-1].Condition == "" {
		s = s[:len(s)-1]
	}
	return s
}

func trimZeros[T comparable](s ...T) []T {
	var zero T
	for len(s) > 0 && s[len(s)-1] == zero {
		s = s[:len(s)-1]
	}
	return s
}