package db

import "time"

// User is an account. Its ID is the OIDC subject for anyone who signed in, or
// LocalUserID for the pre-auth single user (and for local development, where
// StaticResolver still hands out that id).
type User struct {
	ID          string    `json:"id"`
	Email       string    `json:"email"`
	DisplayName string    `json:"display_name"`
	CreatedAt   time.Time `json:"created_at"`

	// PairLang is the X in this writer's (English + X) language pair — "zh"
	// today, "pt-PT"/"fr"/"es" once the langpacks land. It selects the UI copy
	// and dictionary set, not the language they may type in.
	PairLang string `json:"pair_lang"`

	// Direction says which half of the pair is being *learned*. Every pair until
	// now assumed one answer: the writer is native in X and practising English,
	// so hanzi is never tokenized and English is what gets underlined. Turn it
	// around — a native English speaker learning Chinese — and the same pair
	// wants the opposite of nearly every default.
	//
	// It is a separate column from PairLang rather than a second pair code
	// ("zh-learner") because it is a genuinely separate question: the pair says
	// *which two languages*, this says *which way round*. Keeping them apart is
	// what lets fr, es and pt-PT inherit the learner direction later without a
	// second langpack each.
	Direction string `json:"direction"`
}

// Document is a single piece of writing. `Content` is the Tiptap JSON document
// (source of truth for the editor); `ContentText` is the flattened plain text
// kept in sync on every save and fed to the LLM.
type Document struct {
	ID          string    `json:"id"`
	UserID      string    `json:"user_id"`
	Title       string    `json:"title"`
	Content     string    `json:"content"`      // Tiptap JSON
	ContentText string    `json:"content_text"` // plain text for the LLM
	Tone        string    `json:"tone"`         // target writing tone; steers LLM advice
	WordCount   int       `json:"word_count"`
	CreatedAt   time.Time `json:"created_at"`
	UpdatedAt   time.Time `json:"updated_at"`

	// PreserveHistory opts this document out of auto-snapshot pruning so its
	// full writing trail survives as authorship evidence (see the passport).
	PreserveHistory bool `json:"preserve_history"`
}

// DocumentVersion is a point-in-time snapshot of a document's body, captured so
// a writer can recover from a bad edit or an unwanted change. `Content` mirrors
// the document's Tiptap JSON at snapshot time; `Kind` records why it was taken
// (see the kind constants). List responses omit the heavy Content/ContentText
// fields (the `omitempty`-friendly zero strings) and load them only on preview
// or restore.
type DocumentVersion struct {
	ID          string    `json:"id"`
	DocID       string    `json:"doc_id"`
	Title       string    `json:"title"`
	Content     string    `json:"content,omitempty"`      // Tiptap JSON; omitted in list view
	ContentText string    `json:"content_text,omitempty"` // plain text; omitted in list view
	WordCount   int       `json:"word_count"`
	Kind        string    `json:"kind"` // auto | manual | pre_restore
	CreatedAt   time.Time `json:"created_at"`

	// ContentHash chains this snapshot to the previous one (PrevHash), so a
	// history that was edited or thinned after the fact fails verification.
	// Both are empty for snapshots taken before the chain existed. Omitted from
	// list responses; the passport loads them explicitly.
	ContentHash string `json:"content_hash,omitempty"`
	PrevHash    string `json:"prev_hash,omitempty"`
}

// Document version kinds, mirrored from the schema CHECK constraint.
const (
	VersionKindAuto       = "auto"        // throttled background snapshot on save
	VersionKindManual     = "manual"      // explicit "save a restore point"
	VersionKindPreRestore = "pre_restore" // safety copy taken just before a restore
)

// Tag is a user-scoped label for organizing documents. `Color` is a palette key
// (rose, mint, peach, lavender, sky, honey) the frontend maps to a CSS color;
// storing the key (not a hex value) keeps tags in step with the design tokens.
// `DocCount` is populated only by the tag-list endpoint (how many documents wear
// the tag); it's omitted from per-document tag lists.
type Tag struct {
	ID       string `json:"id"`
	Name     string `json:"name"`
	Color    string `json:"color"`
	DocCount int    `json:"doc_count,omitempty"`
}

// Tag color palette keys, mirrored on the frontend. Kept small and aligned with
// the existing design tokens; unknown values fall back to rose client-side.
const (
	TagColorRose     = "rose"
	TagColorMint     = "mint"
	TagColorPeach    = "peach"
	TagColorLavender = "lavender"
	TagColorSky      = "sky"
	TagColorHoney    = "honey"
)

// Suggestion is a single LLM-proposed edit anchored to a span of the document.
//
// FromPos/ToPos are plaintext offsets into ContentText for server-side use only;
// the frontend re-anchors by matching the `Original` string in ProseMirror
// coordinates at render time (spec Note #6). `Replacement` is empty for `voice`
// flags — those are awareness-only, with no correction to apply.
type Suggestion struct {
	ID          string    `json:"id"`
	DocID       string    `json:"doc_id"`
	FromPos     int       `json:"from_pos"`
	ToPos       int       `json:"to_pos"`
	Original    string    `json:"original"`
	Replacement string    `json:"replacement"`
	Explanation string    `json:"explanation"`
	Type        string    `json:"type"`   // grammar | phrasing | idiom | clarity | translate | voice | collocation
	Status      string    `json:"status"` // pending | accepted | rejected
	// Source names the engine that proposed the edit, not its family: an offline
	// rule and the model can both propose a collocation, and the writer is never
	// told which one spoke. It exists so each pass can replace its own rows.
	Source    string    `json:"source"` // llm | local
	CreatedAt time.Time `json:"created_at"`
}

// Suggestion type and status values, mirrored from the schema CHECK constraints.
const (
	SuggestionTypeGrammar     = "grammar"
	SuggestionTypePhrasing    = "phrasing"
	SuggestionTypeIdiom       = "idiom"
	SuggestionTypeClarity     = "clarity"
	// A span she wrote in her own language, rendered into English. Not a
	// correction — nothing was wrong with it — which is why it is its own type
	// rather than a clarity fix: the card is the pair model's flagship moment
	// (SUGGESTIONS §1), and labelling it "Clarity" reads as a tidy-up of her
	// first language. The model isn't asked for this label; it is derived from the
	// span itself (see suggestions/language.go), so it can't drift.
	SuggestionTypeTranslate   = "translate"
	SuggestionTypeVoice       = "voice"
	SuggestionTypeCollocation = "collocation"
	SuggestionTypeMechanics   = "mechanics" // deterministic rule-based pass (no LLM)

	// Who proposed it. The offline rule pack ('local') runs on every edit inside
	// the browser and survives a VPN-down box; the model ('llm') adds the long
	// tail when it is reachable.
	SuggestionSourceLLM   = "llm"
	SuggestionSourceLocal = "local"

	SuggestionStatusPending  = "pending"
	SuggestionStatusAccepted = "accepted"
	SuggestionStatusRejected = "rejected"
)